What is knowledge? It’s an awareness that something your head corresponds to reality. Of course, there may be justification needed to verify that what’s in your head does actually correspond with reality. Otherwise there is no way of verifying that the thing corresponds with reality. And if you don’t know that it corresponds with reality, it’s not knowledge.
But if your thought corresponds with reality, justified or not, it is true. Wait. If you believe that bigfoot exists [assuming he does] without reason to believe so, is it knowledge? It can’t be. There is no reason to think that the proposition, “Bigfoot exists” is true. You just believe that bigfoot exists.
The question becomes How do you know it’s true? Because it can only be knowledge if it’s true. The only way to know it’s true is justification. So the only way to verify that your belief that bigfoot exists is true is to have reason to believe that bigfoot exists in reality. Otherwise, it is not knowledge. It’s fantasy.